Saltpack module

# File lib/saltpack.rb, line 60
def self::armor( input, **options )
        return Saltpack::Armor.armor( input, **options )
end

# File lib/saltpack.rb, line 78
def self::calculate_recipient_hash( header_hash, index, keypair1, keypair2 )

        # 9. Concatenate the first 16 bytes of the header hash from step 7 above, with the
        # recipient index from step 4 above. This is the basis of each recipient's MAC
        # nonce.
        mac_key_nonce_prefix = header_hash[0, 16]
        basis = mac_key_nonce_prefix + [ index ].pack('Q>')

        # Clear the least significant bit of byte 15. That is: nonce[15] &= 0xfe.
        nonce1 = basis.dup
        nonce1[15] = (nonce1[15].ord & 0xfe).chr

        # Modify the nonce from step 10 by setting the least significant bit of byte
        # That is: nonce[15] |= 0x01.
        nonce2 = basis.dup
        nonce2[15] = (nonce2[15].ord | 0x01).chr

        # Encrypt 32 zero bytes using crypto_box with the recipient's public key, the
        # sender's long-term private key, and the nonce from the previous step.
        # Encrypt 32 zero bytes again, as in step 11, but using the ephemeral private
        # key rather than the sender's long term private key.
        box1 = RbNaCl::Box.new( *keypair1 ).encrypt( nonce1, ZEROS_32 )
        box2 = RbNaCl::Box.new( *keypair2 ).encrypt( nonce2, ZEROS_32 )

        # Concatenate the last 32 bytes each box from steps 11 and 13. Take the SHA512
        # hash of that concatenation. The recipient's MAC Key is the first 32 bytes of
        # that hash.
        mac_hash = RbNaCl::Hash.sha512( box1[-16..] + box2[-16..] )

        return mac_hash[ 0, 32 ]
end

# File lib/saltpack.rb, line 67
def self::dearmor( input_chars, **options )
        return Saltpack::Armor.dearmor( input_chars, **options )
end

# File lib/saltpack.rb, line 53
def self::decrypt( message, recipient_key )
        msg = Saltpack::Message.read( message, recipient_key )
        return msg.decrypt
end

# File lib/saltpack.rb, line 46
def self::encrypt( message, sender_key, *recipient_public_keys, **options )
        msg = Saltpack::Message.new( message, sender_key, *recipient_public_keys, **options )
        return msg.to_s
end